BOAC,
It has been mentioned that the SOP was selected/selected, due to lack of approval of anything better. Which would lead toward the VOR rather than the FAT.
I have a suspicion that this trench is deeper and more aggressive than it may appear:
It is difficult to scale its depth from that photo.
If the aircraft started a go-around (ie application of ga thrust and gear up) but for
some reason rapidly headed
down, then it may well have hit hard and more nose down than initially imagined (as per the eye witness).
A nose down attitude would explain the lack of frontal remains - most identifiable bits seem to be from wing root backwards.
A hard vertical g on impact could cause the wing roots to snap (allowing the wing assemblies to travel further before stopping). The tail assembly would be hard to guess, but it clearly has done some acrobatics - given the broken fin tip and the final orientation - but the fact that it's intact adds weight to a nose down impact.